This career development award proposal (Neurobehavioral Study of Graphic Warnings on Adolescents At Risk for Nicotine Dependence) will facilitate the candidates' transition to independence in prevention research by applying her rigorous scientific training and her recent post-doctoral work on neuroimaging of public health communications to an acute issue of smoking in adolescents. The training phase will enhance the readiness of the applicant for the independent research project through a personalized training program in: (a) Risk behavior and cognition in adolescent smokers; (b) Nicotine dependence; (c) Clinical neurobiology of addiction; (d) Developmental neuropsychology and neuroimaging; and (e) Tobacco control policy. According to the Surgeon General (2012), 88% of adult daily smokers start smoking before the age of 18 and two thirds of them become daily smokers by that age. Despite such heightened vulnerability, neurobiological data on the strategies to prevent the initiation and progression of smoking in adolescents are lacking. Graphic warning labels (GWLs) is a prevention strategy that has been intensely debated in the US. The proposed GWLs consist of a textual warning mandated by law and an emotionally arousing image depicting the negative health consequences of smoking. Dearth of objective experimental data on the effects of GWLs has been cited as a key obstacle to their implementation in the US. This project will take a unique trans-disciplinary approach to fill this knowledge gap at the clinical and neurophysiological levels. Adolescent smokers will be exposed to GWLs rated either high or low on the emotional reaction scale (High ER GWL vs Low ER GWL) over a 4-week period using mobile devices. Dependent variables will be brain response to GWLs measured by functional magnetic resonance imaging (fMRI) and cigarette consumption indexed by urine cotinine levels (biochemical marker of smoking), as well as self-report measures of persuasion. Primary (clinical) hypothesis is that High ER GWL group will exhibit greater reduction in urine cotinine and greater intention to quit smoking after the 4-week exposure period than Low ER GWL group. Based on preliminary data and literature pointing to the mPFC and the amygdala as key opponent brain regions mediating brain response to anti-smoking messages, the neuroimaging hypothesis is that acute exposure to high ER GWLs will be associated with stronger amygdala and mPFC responses than low ER GWLs. Furthermore, brain activation in the medial prefrontal cortex (mPFC) in response to GWLs at the first fMRI session will predict urine cotinine levels after the 4-week GWL exposure. The project will advance our understanding in communicating health promoting messages with adolescents and help development of evaluation for effectiveness of such messages.